Electric arc welding gun having a nozzle with a removable metal liner to protect the nozzle from weld splatter

ABSTRACT

The welding gun construction utilizes a nozzle member having an opening for directing an inert gas against the work to be welded. A tubular welding tip is disposed centrally within such opening to guide a welding wire toward the work. A welding arc is drawn between the work and the wire. A tubular metal liner is received within the opening to protect the nozzle member from weld splatter, which comprises molten metal globules thrown up from the welding area. The solidified weld splatter accumulates within the liner, which can be removed and disposed of as needed, before the weld splatter builds up to a thickness sufficient to cause a short circuit between the welding tip and the nozzle member. A new liner is then inserted into the nozzle. The liner is formed with a retaining element whereby the liner is held within the nozzle against accidental dislodgement. Such retaining element may take the form of an oval portion, one or more spring fingers bent outwardly from the liner, or a dimple portion formed by outward deformation of the liner. A pocket or tapered portion may be formed within the nozzle member to retain the outwardly projecting fingers or dimples. The liner may also be arranged for insertion into the nozzle from the rear, and may be retained in the nozzle by an outwardly projecting flange on the rear portion of the liner.

United States Patent Borneman 154] ELECTRIC ARC WELDING GUN HAVING ANozzLE WITH A REMOVABLE METAL LINER TO PROTECT THE NOZZLE FROM WELDsPLATTER 5 [72] Inventor: Lawrence A. Borneman, 411 W.

Ethel Ave., Lombard, Ill. 60148 [22] Filed: March 9, 1970 [21] Appl.No.: 17,361

52 US. C1. ....239/591, 219/121 P 51 Int. Cl. ..B05b 1/00 [58] Field orSearch .239/591; 175/340, 393; 285/175, 334.4, 345, 238; 219/121 P [56]References Cited UNITED STATES PATENTS 3,562,486 2/1971 Hatch et al..219/i21 P 2,944,140 7/1960 Giannini et al ..219/121 P 1,950,947 3/1934Mulroyan ..285/l76 1,039,354 9/1912 Bonadio. ..285/l75 x 1,794,9553/1931 Gordon ..285l334.4 x 2,682,429 6/1954 FOI'IiHO .239/591 1,538,0075/1925 Schellin ..285/345 x 2,896,698 7/1959 Zebrick .239/591 x FOREIGNPATENTS 0R APPLICATIONS 205,512 1/1957 Australia .239/591 1451 Sept. 12,1972 Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Thomas C.Culp, Jr. Att0rney--Burmeister, Palmatier & l-lamby [5 7] ABSTRACT Thewelding gun construction utilizes a nozzle member having an opening fordirecting an inert gas against the work to be welded. A tubular weldingtip is disposed centrally within such opening to guide a welding wiretoward the work. A welding arc is drawn between the work and the wire. Atubular metal liner is received within the Opening to protect the nozzlemember from weld splatter, which comprises molten metal globules thrownup from the welding area. The solidified weld splatter accumulateswithin the liner, which can be removed and disposed of as needed, beforethe weld splatter builds up to a thickness sufficient to cause a shortcircuit between the welding tip and the nozzle member. A new liner isthen inserted into the nozzle. The liner is formed with a retainingelement whereby the liner is held within the nozzle against accidentaldislodgement. Such retaining element may take the form of an ovalportion, one or more spring fingers bent outwardly from the liner, or adimple portion formed by outward deformation of the liner. A pocket ortapered portion may be formed within the nozzle member to retain theoutwardly projecting fingers Or dimples. The liner may also be arrangedfor insertion into the nozzle from the rear, and

may be retained in the nozzle by an outwardly projecting flange on therear portion of the liner.

15 Claims, 16 Drawing Figures ELECTRIC ARC WELDING GUN HAVING A NOZZLEWITH A REMOVABLE METAL LINER TO PROTECT THE NOZZLE FROM WELD SPLA'ITERThis invention relates to a new and improved con struction for weldingguns of the type utilizing a nozzle to direct inert gas against the workto be welded so as to shield the welding area from exposure to theoxygen and nitrogen in the surrounding atmosphere. A welding gun of thistype generally utilizes a guide tube having a tip portion within thenozzle to guide a welding wire or rod toward the work. The welding arcis drawn between the work and the welding wire or rod. The guide tip forthe welding wire is disposed axially in the nozzle opening, so that thestream of inert gas surrounds and encloses the wire and the welding arc.

Problems have been encountered in connection with such welding guns, dueto the accumulation of weld splatter within the nozzle, particularlynear its front end, which has the maximum exposure to the arc. The weldsplatter comprises globules of molten metal which are thrown up into thenozzle during the welding operation. The globules solidify when theystrike the inside of the nozzle, and manyof them adhere to the nozzle.The accumulation of the weld splatter gradually builds up until it maycause a short circuit between the central welding tip and the nozzle.The accumulated weld splatter also obstructs the flow of the inert gas.

When the nozzle becomes clogged, the nozzle must be removed and cleanedout, or replaced with a new nozzle. The removal of the accumulated weldsplatter can be a difficult operation and may require the reboring orreaming of the opening in the nozzle. The necessity for removing theweld splatter shortens the useful life of the nozzle.

One principal object of the invention is-to eliminate the problems dueto the accumulation of weld splatter in welding nozzles.

Thus, the present invention preferably provides a disposable metal linerwhich is inserted into the welding nozzle to protect the nozzle fromweld splatter. One or more retaining elements are provided on the linerto hold it within the opening in the nozzle, against accidentaldislodgment. Instead of being deposited on the inner surface of thenozzle, the weld splatter is deposited on the liner. When the wallsplatter builds up to excessive thickness, the liner is simply removedand replaced with a new liner. The cost of the liner is very small,because it may be made of thin sheet metal, or in the form of athin-walled tube. It is an easy matter to slip the old liner out of thenozzle and to slip in a new liner.

The liner may be retained by forming a portion of its annular wall in anoval shape so that the oval portion must be compressed to insert theliner into the nozzle. When the liner has been inserted, the ovalportion springs outwardly so that the liner is frictionally retained inthe nozzle.

An alternative construction is to form outwardly projecting elements onthe liner, for frictionally engaging the inside of the nozzle. Suchprojections may take the form of spring fingers or dimple shapedprotrusions. In some cases, the nozzle may be formed with an internalannular groove, or an internal tapered surface, to engage the outwardprojections on the liner.

Another alternative construction is to split the liner so that it has agap in its circumference. The liner is made larger than the opening inthe nozzle so that the liner must be compressed for insertion into theopening. The liner then springs outwardly and is frictionally retained.

The liner may also be arranged for insertion into the nozzle from therear end thereof. This requires removal of the nozzle from the weldinggun. The liner is retained by an outward flange or other similar elementthereon, adapted to engage a shoulder within the nozzle. The liner maybe held against the shoulder by a sleeve or bushing within the nozzle.

Further objects, advantages and features of the present invention willappear from the following description, taken with the accompanyingdrawings, in which:

FIG. 1 is a longitudinal section taken through a welding gun, to bedescribed as an illustrative embodiment of the present invention.

FIG. 2 is a front elevation of a disposable metal liner, adapted to beinserted and retained within the welding nozzle shown in FIG. 1.

FIG. 3 is a longitudinal section taken along the line 3-3 in FIG. 2.

FIG. 4 is a rear elevation of the liner.

FIG. 5 is a front elevation of a modified liner utilizing spring fingersto retain the liner in the welding nozzle.

FIG. 6 is a longitudinal section, taken generally along the line 6-6 inFIG. 7.

FIG. 7 is a rear elevation of the liner shown in FIGS. 5 and 6.

FIG. 8 is a longitudinal section taken along the line 88 in FIG. 9, andshowing another modified liner utilizing outwardly formed dimples toretain the liner in the welding nozzle.

FIG. 9 is a rear elevation of the liner shown in FIG. 8.

FIG. 10 is a fragmentary longitudinal section showing a modified nozzleconstruction, providing an internal groove or pocket to assist in theretention of the liner.

FIG. 11 is a fragmentary longitudinal section showing another modifiednozzle construction, utilim'ng a tapered internal surface to assist inretaining the liner.

FIG. .12 is a front elevation of another modified liner which is splitto form a gap in its circumference.

FIG. 13 is a central longitudinal section taken generally along the line13-13 in FIG. 12.

FIG. 14 is a rear elevation of the liner shown in FIGS. 12 and 13.

FIG. 15 is a fragmentary longitudinal section showing another modifiedliner and nozzle construction.

FIG. 16 is a front elevation of the construction shown in FIG. 15.

FIG. I considered in greater detail, illustrates an embodiment of theinvention, in the form of a nozzle assembly 20 for a welding gun 22. Itwill be seen that the welding gun 22 comprises a body 24 which may bemade of metal covered with rubber or some other insulating material. Anyother suitable material may be employed in the body 24.

As illustrated, an adapter bushing or extension 26 is mounted on atubular guide 28, which in turn is mounted on the body 24. An axial bore30 is formed in the tubular guide 28 to receive the welding member 32,

which is illustrated as a wire but may comprise a rod or the like. Itwill be understood that the welding arc is drawn between the wire 32 andthe work to be welded.

Passages 34 are formed in the tubular guide 28 to carry the inert gas,which may comprise helium or argon, for example. The passages 34 extendlongitudinallyalong the tubular guide 28 and connect with ports 36 whichextend outwardly near the outer end of the guide 28.

As shown, the tubular guide 28 has an externally threaded portion 37which is mated with an internally threaded bore 38 in the adapterbushing 26. Preferably, the bushing 26 is made of electricallyinsulating material. The guide 28 may be screwed into an internallythreaded bore 39 in the body 24.

The tubular guide 28 is fitted with a removable welding tip member 40having an axial bore 42 therein adapted to carry the welding wire 32.The tip member 40 is made of copper or some other electricallyconductive material because it carries the welding current to the wire32. As shown, the tip member 40 has an externally threaded inner endportion 44, adapted to be screwed into an internally threaded bore 46 inthe guide 28. Because it carries the welding current, the guide 28 ismade of metal or some other electrically conductive material.

A nozzle member 48 is removably connected to the body 24 of the weldinggun 22/Preferably, the nozzle member 48 is mounted on the bushing 26which serves as an extension of the body 24. Screw threaded elements areemployed in this case to connect the nozzle member 48 to the bushing 26.Thus, the bushing 26 has an externally threaded portion 50, adapted toreceive an internally threaded portion 52 on the rear end of the nozzlemember 48.

The nozzle 48 is preferably made of metal, such as copper, brass,aluminum or the like. A bore or opening 54 is formed in the nozzle 48 tocarry the stream of inert gas. It will be seen that the welding tip 40is centrally disposed in the opening 54. Thus, the stream of inert gassurrounds and shields the welding wire 32 and the welding arc. Theopening 54 in the nozzle 48 is illustrated as being cylindrical, but itmay be tapered in some cases.

In accordance with the present invention, the nozzle 48 is provided witha liner or insert 56 to protect the nozzle from weld splatter. The liner56 is tubular in form and is inserted into the front end of the opening54. Thus, the liner 56 protects the portion of the nozzle which isexposed to the heat of the arc and the splattering of metal from thewelding area. The liner 56 is made of metal such as brass, copper,aluminum or the like.

The front end of the liner 56 is preferably provided with an outwardlyprojecting flange 58 or some similar element, to engage the front end ofthe nozzle 48 so as to limit the extent to which the liner 56 isinserted into the opening 54. The flange 58 also makes it easy to removethe liner 56 from the nozzle 48. In addition, the flange 58 protects thefront edge of the nozzle 48 from weld splatter. Furthermore, the flange58 may be slightly larger in diameter than the adjacent portion of thenozzle 48, the better to shed and deflect weld splatter away from theoutside of the nozzle.

Means are provided on the liner 56 to retain the liner within the nozzle48 against accidental dislodgement. However, the liner S6 is retained insuch a way that it is easy to remove when it needs to be replaced. Inthe construction shown in FIGS. 2-4, the liner 56 is generallycylindrical in shape, but is formed with a rear end portion 60 which isoval or out of round, as shown to best advantage in FIG. 4. The majordimension of the oval portion 60 is greater than the diameter of theopening 54, so that the oval portion 60 must be compressed in order toinsert the liner 56 into the opening 54. When the liner 56 is inserted,the oval portion 60 springs outwardly so that it frictionally engagesthe nozzle 48 within the opening 54. Due to this frictional engagement,the liner 56 is retained inthe opening 54 against accidentaldislodgement. However, the liner 56 can easily be removed so that it canbe replaced with a new liner when the weld splatter accumulates to anexcessive extent on the old liner. The liner 56 is made of thin metal sothat it can easily be sprung or compressed when it is to be insertedinto the opening 54 in the nozzle 48.

FIGS. 5-7 illustrate a modified liner 156 which is formed with outwardlyprojecting elements for frictionally engaging the inside of the nozzle48. Such outwardly projecting elements take the form of one or morespring fingers 160 which are struck from the metal wall of the liner. Itwill be seen that fingers 160 are bent or bowed outwardly for frictionalengagement with the nozzle 48 within the opening 54. The spring fingers160 engage the nozzle 48 within the opening 54. The spring fingers 160engage the nozzle 48 with sufficient force to prevent accidentaldislodgement of the liner 156. However, the liner 156 can easily beremoved from the opening 54 in the nozzle 48. In other respects, theliner 156 of of FIGS. 5-7 is the same as the liner 56 of FIGS. 2-4.Another modified liner 256 is shown in FIGS. 8 and 9. Here again, theliner 256 is generally cylindrical in shape, but is formed with one ormore outwardly projecting dimples 260 for frictionally engaging thenozzle 48 within the opening 54. The dimples 260 are produced by outwarddeformation of the cylindrical wall of the liner 256. Two such dimplesare shown in FIGS. 8 and 9. The illustrated dimples 260 are sphericallycurved in shape.

When the liner 256 is inserted into the opening 54, the dimples 260cause compression of the liner so that the dimples are pressed outwardlyinto firm frictional engagement with the nozzle 48.

The nozzle 48 of FIG. I has a cylindrical bore which is frictionallyengaged by the outwardly projecting element on the liner. However, asillustrated in FIGS. 10 and 11, the nozzle may be modified to assist inthe retention of the liner. Thus, FIG. 10 illustrates a modified nozzle348 having a bore or opening 354. The nozzle 348 is the same aspreviously described, except that a pocket or groove 355 is formed inthe bore 354. In FIG. 10, the liner 156 of FIGS. 5-7 is shown in thebore 354. It will be seen that the spring fingers 160 are adapted tospring outwardly into the groove 355. Thus, the liner 156 is moresecurely retained in the bore 354. It will be understood that the liner256 of FIGS. 8 and 9 can also be inserted into the bore 354. In thatcase, the outwardly projecting dimples 260 will be received in thepocket or groove 355.

FIG. 11 illustrates another modified nozzle 448 having a bore or opening454. in this case, the nozzle 448 is formed with a tapered annularsurface 455 which connects with the rear end of the bore 454. It will beseen that the liner 256 of FIGS. 8 and 9 is mounted within the bore 454.The dimples 260 are in engagement with the tapered surface 455. As theliner 256 is inserted into the nozzle 448, the dimples 260 springoutwardly when they encounter the tapered surface 455. It will beunderstood that the liner 156 of FIGS. 5-7 can also be inserted into thebore 454. In that case, the fingers 160 spring outwardly to engage thetapered surface 455.

FlGS. 12-14 illustrate another modified liner 556 which is generallycylindrical in shape but is formed with an outwardly projecting flange558 at its front end. In this case, the flange 558 is rolled or curledfrom the wall of the liner 556.

To provide for retention of the liner 556, it is split so that a gap 560is formed in its circumference. The initial diameter of the liner 556 ismade greater than the diameter of the opening 54 in the nozzle 48. Thus,the liner 556 must be compressed when it is to be inserted into theopening 54. Such compression closes the gap 560 or at least reduces itswidth. When the liner 556 has been inserted, it springs outwardly intofrictional engagement with the nozzle 48 within the opening 54. Theflange 558 increases the stiffness of the liner 556 so that the springpressure between the liner and the nozzle is increased. The flange 558makes it easy to grip the liner 556 when it is to be removed from thenozzle 48.

H68. 15 and 16 illustrate a modified construction in which both thenozzle and the liner are modified. The liner is inserted from the rearof the nozzle rather than from the front. Thus, the nozzle must beunscrewed from the welding gun when the liner is to be inserted.

Specifically, H65. 15 and 16 illustrate a modified nozzle 648 having abore or opening654 therein. Behind the bore 654, the nozzle 648 has anenlarged bore 655. As previously described, the internally threadedportion 52 is to the rear of the enlarged bore 655.

A liner 656 is adapted to be inserted into the bore 654 through theenlarged bore 655 to the rear of the bore 654. The liner 656 isgenerally cylindrical but is retained by an outwardly projecting flangeor other element 666 at the rear end thereof. The flange 660 is of sucha size that it can be inserted through the enlarged bore 655. The flange666 is engageable with a rearwardly facing shoulder 661 which is formedwithin the nozzle 648 between the bore 654 and enlarged bore 655. Theshoulder 661 retains the liner 656 against forward movement out of thenozzle 648.

To prevent rearward movement of the liner 656 it is preferred to providea bushing or sleeve 663 within the enlarged bore 655 behind the flange660. The bushing 663 is preferably made of an electrically insulatingmaterial. such as a heat resistant plastic. When the nozzle 648 isscrewed onto the bushing 26 the bushing 663 engages the bushing 26 andis pushed forwardly so that it pushes the flange 660 against theshoulder 661.

l claim:

1. An electric arc welding gun construction,

comprising a metal nozzle member having an axial generally cylindricalopening of substantially circular cross section in the outer end portionof said nozzle member for directing an inert gas against the worl: to bewelded,

a tubular metal generally cylindrical tip member disposed centrally insaid generally cylindrical opening and having an axial guide boretherein,

a consumable arc welding member slidably movable through said bore andextending out of said tip member and beyond said opening and the outerend portion of said nozzle member for movement toward the work,

and a tubular generally cylindrical metal liner removably slip fittedwithin said generally cylindrical opening for protecting said nozzlemember from weld splatter,

said metal liner having a substantially larger inner size than the outersize of said tip member to provide an annular space therebetween for thepassage of the inert gas,

. said liner having a retaining element for removably holding said linerin said nozzle member against accidental dislodgment.

2. A welding gun construction according to claim 1,

in which said retaining element of said liner comprises a wall portionthereof formed into an oval shape and having a maximum dimension greaterthan the diameter of said generally cylindrical opening whereby saidwall portion must be compressed to provide for insertion of said linerinto said opening,

said wall portion being effective to spring outwardly against saidnozzle to retain said liner in said openmg.

3. A welding gun construction according to claim 1,

in which said retaining element comprises at least one wall portionprojecting outwardly from said liner and frictionally engageable withsaid nozzle member within said generally cylindrical opening.

4. A welding gun construction according to claim 3,

in which said nozzle member is formed with a pocket within saidgenerally cylindrical opening for receiving and retaining said outwardlyprojecting wall portion.

5. A welding gun construction according to claim 3,

in which said wall portion comprises a spring finger struck from saidliner and bent outwardly therefrom for frictional engagement with saidnozzle member within said generally cylindrical openmg.

6. A welding gun construction according to claim 3,

in which said wall portion comprises an outwardly projectingdimple-shaped deformation on said liner and frictionally engageable withsaid nozzle member within said generally cylindrical opening.

7. A welding gun construction according to claim 4,

in which said nozzle member is formed with a tapered surface within saidgenerally cylindrical opening for engaging and retaining said wallportion.

8. A welding gun construction according to claim 1,

in which said liner comprises means forming an open split in thecircumference thereof and extending entirely through the wall of saidliner,

said liner being of a dimension greater than the size of said openingwhereby said liner must be compressed for insertion into said generallycylindrical opening,

said liner being efiective to spring outwardly against said nozzlemember to retain said liner within said generally cylindrical opening.

9. A welding gun construction according to claim 8,

in which said liner comprises a rolled flange projecting outwardly fromone end of said liner and affording increased spring resistance to thecompression of said liner,

said split extending through said flange.

10. A welding gun construction according to claim 1, 10

said nozzle member having a rearwardly facing annular shoulder in saidgenerally cylindrical opening for engagement by said rear end portion torestrain said liner against forward movement, said liner beinginsertable into said nozzle member from the rear end thereof. 13. Awelding gun construction according to claim 12,

in which said rear end portion comprises an outwardly projecting annularflange on the rear end of said liner. 14. A welding gun constructionaccording to claim 12,

including means within said nozzle member and behind said liner forretaining said rear end portion thereof against said annular shoulder.15. A welding gun construction according to claim 12,

including a bushing within said nozzle member and behind said liner forretaining said rear end portion against said annular shoulder.

1. An electric arc welding gun construction, comprising a metal nozzlemember having an axial generally cylindrical opening of substantiallycircular cross section in the outer end portion of said nozzle memberfor directing an inert gas against the work to be welded, a tubularmetal generally cylindrical tip member disposed centrally in saidgenerally cylindrical opening and having an axial guide bore therein, aconsumable arc welding member slidably movable through said bore andextending out of said tip member and beyond said opening and the outerend portion of said nozzle member for movement toward the work, and atubular generally cylindrical metal liner removably slip fitted withinsaid generally cylindrical opening for protecting said nozzle memberfrom weld splatter, said metal liner having a substantially larger innersize than the outer size of said tip member to provide an annular spacetherebetween for the passage of the inert gas, said liner having aretaining element for removably holding said liner in said nozzle memberagainst accidental dislodgment.
 2. A welding gun construction accordingto claim 1, in which said retaining element of said liner comprises awall portion thereof formed into an oval shape and having a maximumdimension greater than the diameter of said generally cylindricalopening whereby said wall portion must be compressed to provide forinsertion of said liner into said opening, said wall portion beingeffective to spring outwardly against said nozzle to retain said linerin said oPening.
 3. A welding gun construction according to claim 1, inwhich said retaining element comprises at least one wall portionprojecting outwardly from said liner and frictionally engageable withsaid nozzle member within said generally cylindrical opening.
 4. Awelding gun construction according to claim 3, in which said nozzlemember is formed with a pocket within said generally cylindrical openingfor receiving and retaining said outwardly projecting wall portion.
 5. Awelding gun construction according to claim 3, in which said wallportion comprises a spring finger struck from said liner and bentoutwardly therefrom for frictional engagement with said nozzle memberwithin said generally cylindrical opening.
 6. A welding gun constructionaccording to claim 3, in which said wall portion comprises an outwardlyprojecting dimple-shaped deformation on said liner and frictionallyengageable with said nozzle member within said generally cylindricalopening.
 7. A welding gun construction according to claim 4, in whichsaid nozzle member is formed with a tapered surface within saidgenerally cylindrical opening for engaging and retaining said wallportion.
 8. A welding gun construction according to claim 1, in whichsaid liner comprises means forming an open split in the circumferencethereof and extending entirely through the wall of said liner, saidliner being of a dimension greater than the size of said opening wherebysaid liner must be compressed for insertion into said generallycylindrical opening, said liner being effective to spring outwardlyagainst said nozzle member to retain said liner within said generallycylindrical opening.
 9. A welding gun construction according to claim 8,in which said liner comprises a rolled flange projecting outwardly fromone end of said liner and affording increased spring resistance to thecompression of said liner, said split extending through said flange. 10.A welding gun construction according to claim 1, including an annularflange projecting outwardly from the front end of said liner forengaging the front end of said nozzle member to limit the extent of theinsertion of said liner into said generally cylindrical opening and toprotect the tip of the nozzle from weld splatter.
 11. A welding gunconstruction according to claim 10, in which said annular flange isrolled from the body of said liner.
 12. A welding gun constructionaccording to claim 1, in which said retaining element comprises a rearend portion projecting outwardly from said liner, said nozzle memberhaving a rearwardly facing annular shoulder in said generallycylindrical opening for engagement by said rear end portion to restrainsaid liner against forward movement, said liner being insertable intosaid nozzle member from the rear end thereof.
 13. A welding gunconstruction according to claim 12, in which said rear end portioncomprises an outwardly projecting annular flange on the rear end of saidliner.
 14. A welding gun construction according to claim 12, includingmeans within said nozzle member and behind said liner for retaining saidrear end portion thereof against said annular shoulder.
 15. A weldinggun construction according to claim 12, including a bushing within saidnozzle member and behind said liner for retaining said rear end portionagainst said annular shoulder.